Some users who have installed recent Windows 10 updates
including KB4549951 have reported that their user profile with
all the data, customizations and documents weren’t loading when
they logged in. After the updates are applied, Windows 10 boots
with a mysterious temporary user profile bug and it could move
your data or even delete them.
We’ve been reporting about this bug for months and it appears
that the issue is still there, and it could affect anyone. It’s
not clear why or how Windows 10 loads with an entirely new user
A number of users also reported that their
data including documents or pictures disappeared after they
installed Windows 10 KB4549951, which was released on April 14.
After the update is applied, Windows renames normal user
profile folder, then creates and loads a temporary user profile
when the PC boots up.
The original profile is renamed when Windows 10 update is
installed and data including system customizations magically
disappear, but the good news is, the bug does not permanently
delete profile or data for most of the users.
The original profile should still be in C: > Users, but your
data would be in a file ending with “.ooo” or “.bak”.
Fortunately, there are ways to get it back. If you restart
Windows for at least 6 to 8 times, the user profile and the
data should return.
It’s not clear how many restarts are needed, nor whether it
works for everyone. For example, some users reported that their
files completely disappeared and they’re unable to find or
Some users also reported
the problem after updating to Windows 10 version 1909 from 1903
According to multiple Microsoft support staff, you can also
resolve the problem by setting up a new account and then
manually transferring the data from the temporary account over
The more consistent option is to just backup the files stored
in the system drive before installing the updates. You should
always maintain the backup of the data which are on the same
partition as your operating system.